Analysis of gene expression in wheat upon treatment with a novel plant activator
Abstract
English: Plant activators are an exciting alternative to modern day plant pathogen control
procedures. Yet research on plant activators and the mechanisms involved in
their action remains limited. The plant activator used during this study, SS, is a
purified fraction from the commercial product ComCat® with known positive
effects in field trials. The main aims of the study was to confirm the action of SS
on a molecular level in wheat, identify genes involved in the process and
examine the possible mode of action of the activator.
Leaf rust resistant Thatcher+Lr34 and susceptible Thatcher wheat cultivars were
treated with SS and water. SSH was performed on pooled Thatcher+Lr34 RNA
resulting in 562 putatively induced cDNA clones. Of these, 51 were sequenced.
The sequenced clones shared homology with a variety of genes mostly encoding
photosynthetic and metabolic products, as well as one plant defence related
gene encoding Ptr ToxA binding protein1. Expression analysis confirmed a
characteristic two step induction pattern in Thatcher+Lr34 confirming the induced
gene expression
It was concluded that SS application in wheat increases photosynthetic and
metabolic capacity on a molecular level thereby confirming field results. The
induction of expression of TaThf1 (Ptr ToxA Binding protein1) by SS suggested a
possible unique role in plant defence against pathogens. Afrikaans: Die gebruik van plantaktiveerders bied ‘n opwindende alternatief vir moderne
tegnieke om plantpatogene te beheer. Ten spyte hiervan is baie min navorsing
op die gebied van plantaktiveerders en hul meganismes tot dusver gedoen. ‘n
Gesuiwerde fraksie van die kommersiële produk, ComCat®, bekend as SS, is as
plantaktiveerder gebruik gedurende die studie, omdat dit positiewe resultate in
veldproewe gelewer het. Die hoof doelwitte van hierdie projek was om die aksie
van SS op molekulêre vlak in koring te ondersoek, om gene te identifiseer wat in
die proses betrokke is asook om ‘n moontlike meganisme van werking vir SS
daar te stel.
Thatcher+Lr34, weerstandbiedend teen stamroes, en vatbare Thatcher plante is
met SS en water behandel. Saamgepoelde RNA van Thatcher+Lr34 plante is
tydens SSH gebruik. In totaal is 562 moontlik geïnduseerde cDNA klone
geïdentifiseer. Die DNA basisvolgorde van 51 van die klone is bepaal. Die
meerderheid van die klone het homologie op geen vlak getoon met gene wat vir
fotosintetiese en metaboliese produkte kodeer. Een kloon het homologie met die
geen wat kodeer vir Ptr ToxA bindingsprotiën1 wat betrokke is by
plantverdediging getoon.
Ten slotte is bewys dat behandeling met SS die fotosintetiese en metabolise
kapasiteit van koring op molekulêre vlak verhoog. Die induksie van TaThf1
uitdrukking na SS behandeling dui ook op ‘n moontlike unieke rol van SS in
plantverdediging.